In the practice of orthodontics, an orthodontist may use bracket appliances and an archwire to move and position teeth in a patient's mouth. The brackets are fixed to several teeth, generally, to all of the patient's anterior teeth and to the first molars. Archwires are loosely pinned to the brackets to provide archform and the function of leveling the teeth.
Auxiliary appliances can be used in conjunction with the brackets and archwires to apply rotating, tipping, and torquing forces to an individual tooth in an effort to correct the position of the tooth in relation to the other teeth in the patient's mouth. Rotating forces will cause a tooth to rotate about its long axis. Tipping forces will cause the movement of a tooth about its longitudinal axis in a mesial-distal direction. Torquing forces will cause the movement of a tooth about its longitudinal axis in buccal-lingual direction.
One such auxiliary appliance is an uprighting spring. Generally, an uprighting spring connects between the bracket and archwire, and applies one or a combination of tipping and rotating forces to any tooth. The wire-form of conventional uprighting springs have a relatively complex structure with many bends, twists and turns. The conventional uprighting spring incorporates a helix structure as a means for delivering force to the tooth.
Several disadvantages are inherent in the helix force generator and complex wire-form structure. The shape of the complex structure, the helix in particular, provides an ideal place for the build up and retention of plaque. It is common for a patient to experience gingival irritation near the location of the helix. Mechanically, due to the environment in which the helix is located, a stainless steel uprighting spring may lose force with time and may need to be replaced or reactivated. This results in the patient requiring more appointments and chair time with the orthodontist, over and above the initial chair time required to install the complex structured uprighting spring.